Design of a High Frequency DAB-Type Microinverter for Photovoltaic Application

This article presents a design of a high frequency DAB-type microinverter with single stage structure. The proposed inverter is similar to the dual active bridge (DAB) converter in circuit topology, where the control strategy is developed based on the extended phase-shift (EPS) mode. Compared with the conventional two-stage inverter, it reduces the transformer turns ratio by adding a capacitor
$\boldsymbol{C}_{\mathbf{boost}}$
on the secondary side. The control of phase-frequency coupling can realize the linear correspondence between control variables and the output current, so that the output can be controlled quickly. The control loop for current combining feedforward and feedback can have both rapidity and accuracy of output. A 300W prototype was designed to verify the linearization control scheme of the microinverter.